[2 +2] Photocycloaddition of acetylacetone to naphthoates: a diverse addition pattern

Abstract

Acetylacetone photolytically adds to 1-and 2-naphthoates with or without acid catalysis by the [2 + 21 mode resulting in divergent regioselectivities; the structure of a secondary intramolecular cyclization product was ascertained by means of X-ray crystallography.

Synthesis of 3‐Oxatricyclo[7.2.0.01,5]undeca‐7,10‐dienes through Intramolecular Photocycloaddition Reactions of Alkenes to 1,8 a‐Position of Naphthalene Ring

“…Photocycloaddition reactions between naphthalene rings and alkenes are known to have five modes as shown in Scheme 1. Reaction at the 1,2‐position that have high double bond character is the most common, and is described in many reports [13–70] . Reaction at the 1,3‐position via a biradical leads to compounds having a 3‐oxatricyclo[3.3.0.0 2,8 ]oct‐3‐ene skeleton, which was also shown in our earlier extensive studies [17,44,66,67,70–74] .…”

“…The methoxy-substituted product trans-7 ac was crystallized, and the X-ray crystal structure was analyzed, confirming that it is the trans isomer (Figure 1c). [88] In the photoreactions of (E)-6 ba-bf, which were introduced a methoxy group at the 6-position of the naphthalene ring, the overall yield decreased to 17-53 % (entries [30][31][32][33][34][35]. As for the trans/cis ratio, the ratio of cis isomer increased slightly compared to the reactions of substrates without the methoxy group, even though the trans isomer was preferentially obtained.…”

The Application of Cyclobutane Derivatives in Organic Synthesis

“…For instance, with a 10:1 ratio, 60% of methyl 1-naphthoate was photolyzed in 8 h to give 39 with an isolated yield of 30%. However, under a similar condition, photolysis of acetylacetone and methyl 2-naphthoate (40) with the ratio of 10:1 in acetonitrile for 15 h caused 60% conversion, and diketones 41 and 42 were isolated in 37% and 3% yields, respectively 17 (46) and cyclohexene, and formed 48 through a de Mayo process 19 .…”